Onset of Solar Modulation in the Outer Heliosphere as Seen in Anomalous Cosmic Rays
We examine intensities and gradients of anomalous cosmic rays determined from observations on the Voyager 1 and 2 spacecraft to study the rapid increase in solar modulation that begins near mid-2000. We suggest that these effects are due to the arrival in the region of the spacecraft of complex magnetic field topologies associated with the reversal of the Sun's magnetic field.
Additional Information© Copernicus GmbH. Provided by the NASA Astrophysics Data System. Th.is work was supported by NASA under contract NAS7-918. We thank the Wilcox Solar Observatory for the heliospheric Lill values and coronal field maps (lmp://quake.stanford.edu/ wso/wso.html ). We thank the MIT Space Plasma Group for supplying the daily averaged IMP-8 solar wind speeds (ftp://space.mit.edu/pub/plasma/imp/www/imp.html). We thank the ACE/SWEPAM team for supplying lhe ACE solar wind speeds (http://www.srl .cal tech.edu/ ACE/ ASC/level2/index.html).
Published - 2001-15.pdf